Audio and video production is essential to the creative process in many disciplines, such as film, video game development, and performing arts. Professionals and hobbyists in these disciplines are always looking for new tools and methods to manipulate audio and video signals to create desirable changes to these signals. Sometimes, in moments of exploration or desperation, tools are operated outside of their typical operating parameters, causing unexpected performance. History has shown us that this is not always bad. Guitar pedals, such as the fuzz pedal or the wah-wah pedal, emerged from the realization that creating deliberate distortion or modulation in an audio signal by causing a portion of the audio signal path to, for example, operate outside of specification, be deliberately degraded, or attenuated, can cause desirable results.
Over many years, many different signal processing circuits and manipulation techniques have been developed and are in use today. Similar signal processing circuits and manipulation techniques are also used by the video production community to cause desirable results in video signals.
A commonality of these signal processing circuits is the need for electrical power. Several solutions for this power requirement are in place today. Some of these solutions include batteries, and step down transformers, typically used to convert alternating current from a wall outlet to low voltage direct current for use by a low power signal processing circuit, or a low-voltage alternating current for further manipulation by the signal processing circuit.
Nearly all such power supplies used by signal processing circuits are not controllable by the user. Making changes to the power supply can damage some types of equipment. Therefore, the power supplies that are user controllable are typically restricted to changing only the output voltage in order to precisely match or step down the available power to the power requirements of the signal processing circuit, generally by operating a switch on the power supply that taps into the outputs of different secondary wires in the associated power transformer. Furthermore, it is generally the case that a power supply commercially provided with a given signal processing circuit will provide a fixed voltage and peak current rating in an attempt to keep the signal processing circuit operating at peak performance without requiring additional configuration from the end user.
Because of all this, users do not attempt to operate signal processing equipment with mismatched or underpowered power supplies, and if they do, it is generally the result of accidentally grabbing the wrong power supply, or accidentally setting the output voltage incorrectly on a variable power supply, or mistakenly grabbing a dead battery. In all of these cases the signal processing equipment usually does not work as expected, if at all.
However it is also notable that many signal processing circuits have designs that permit them to operate within a range of currents and voltages, albeit with potentially degraded performance. A good example of such tolerance is a battery powered guitar pedal with a dying battery installed. When the battery finally dies, it does not destroy the guitar pedal, rather the design of the signal processing circuit within the guitar pedal is able to withstand the battery dying. I have found that the signal travels through an additional palette of changing timbres, above and beyond the palette of timbres produced by the signal processing circuit operating normally, as the battery dies. This is because the dying battery is increasingly depriving the signal processing circuit of the power needed for typical operation, which I have found produces an additional desirable result in many signal processing circuits. Unfortunately, the result is often short lived and not appropriately controllable, offering limited creative exploration of this phenomena.